Military branches employ a significant number of Thurston County residents. The majority of these jobs occur at Joint Base Lewis-McChord. The base employs more than 38,000 military personnel and 14,000 civilians, making it one of the top 5 employers in Washington in recent years (ahead of Microsoft, but behind Boeing).

Between 2012 and 2016, an average of about 3,700 resident active-duty military personnel lived in Thurston County, an increase from 2,000 people in 2000.